Often in routine imaging examinations of the abdomen, either an ultrasound or CAT scan of the abdomen, a cyst is found in the liver. The vast majority of these correspond to simple hepatic cysts.
The term cyst refers to any lesion that is filled with liquid content. Simple hepatic cysts have imperceptible walls and that do not communicate with the bile duct. They range in size from millimeters to giant lesions. They are more common in women, particularly large symptomatic cysts.
Most simple hepatic cysts cause no symptoms. When a cyst is large (greater than 4 cm), it may have nonspecific symptoms such as abdominal pain, early satiety or nausea. However, the evaluation of these symptoms should always be careful as these complaints may arise from other causes such as irritable bowel syndrome, lumbago, or cholelithiasis (gallbladder stones). Much less often a large cyst may be complicated by bleeding, torsion, infection or rupture.
A typical simple cystic liver lesion found on ultrasound may not require additional studies when small to moderate. On ultrasound, the cyst is seen as an anechogenic lesion without septa, with imperceptible wall and posterior reinforcement.
CT and MRI show a water density lesion density of water that is not enhanced with intravenous contrast.
The differential diagnosis of simple liver cyst includes the following conditions:
- Abscess: Usually the presence of symptoms such as pain and fever, laboratory abnormalities such as elevated C-reactive protein, associated with imaging features (peripheral enhancement) are easy to distinguish in most cases.
- Hydatid cyst: Hydatid cysts often have calcifications in the cyst wall and “complex” adjacent smaller or multiloculated cysts with thick walls and internal echoes corresponding to parasitic structures can be distinguished. Hydatid serology is frequently positive.
- Polycystic disease: The presence of multiple cysts in the liver suggest the diagnosis of polycystic liver disease, most often associated with renal cysts (autosomal dominant polycystic kidney disease, ADPKD). However, in other cases, the cysts are found only in the liver (autosomal dominant polycystic liver disease).
- Cystadenoma: This is a rare benign tumor. It has thickened walls and is often multiloculated. Treatment is resection.
- Cystadenocarcinoma: An uncommon malignant tumor, probably derived from the malignant transformation of a cystadenoma. Treatment also is surgical.
- Necrotic tumor: Some malignant tumors metastatic and primary liver occasionally may have a liquefied necrotic component that may seem like a simple cyst, however, clinical symptoms usually allow differentiation.
The vast majority of simple hepatic cysts require no treatment. When a cyst is large (greater than 4 cm), it is usually recommended controlling images, for which an ultrasound is usually sufficient. If the cyst does not grow after 2 or 3 years, there is no need for more controls.
In those cases when the cyst is large and symptomatic, treatment is surgery. While there are several surgical options, the most widely used is the unroofing of the cyst, either by open surgery or laparoscopy. The drainage of the cyst by aspiration is not a satisfactory option since the cyst usually recurs.